Grinding machine



`Allg. 19, 1941. R, H, CRAMER V2,253,324

GRINDING MACHINE Filed Sept. 24, 1957 2 Sheets-Sheet 1 Aug. 19', 1941.R, H. CRAMER 2,253,324

' GRINDING MACHINE Filed Sept. 24.1937 2 Sheets-Sheet 2 /NVE/v fof?.RAYMOND H CRA/VER,

Patented Aug. 19, 1941 .UNITED I STATES ENT i GFF ICE GRINDING RaymondH. Cramer, Newark,A N.\J.,` assigner to VGeneral -Motors Corporation,Detroit, Mich., a corporation of `Delaware F h A h Application septmiier24, 1937, serial No. 165,565

5 claims. (orsi-icm This invention relates` to grinding `machines and;methods and comprises all of the features and aspects `of noveltyhereindisclosed. In centerless grinding bythethrougn feed method, roundness ofthe; Work is improved by passing the` work several times through thegrinding zone, the` position of the `Work bladek being different forsuccessive passes. In ,other Words, the work is initially ground aboveor belowthe line ofcenters of the grinding andthe regulating Wheels, lOolutiona'ccurately generated by the machine. the subsequent passes beingsuccessively nearer The numeral indicates a support or bed which to theline of centers. This requires either sevis oscillated around a verticalaxis I by any eral machines each with adiflerent setting or a suitablemechanism. A base plate l2 having a series of set-ups for one machine. gstandard I4 is secured by :bolts I6 tothe bed An object of the inventionis to provide an iml and has a bearing I8` for a` rotating shaft 2U.proved grinding machine and method for com- One end ofthe shaft isreduced in diameter and pletely finishing a surface of revolution in asingle carries a Worm Wheel 22 driven by a Worm 2li pass through thegrinding zone and obtaining a, held between thrust bearings on ahorizontal progressive true roundness of the generated surshaft 26'which is journalled in bearing lugs 2B face in any plane normal to theaxis of the piece.` onthe standard. A pulley 30 drives the shaft 2tAnother object is to provide an improved grindand, through the yWorm,gearing, turns the shaft ing machine and method for acurately generat-Z-Uclockwisevat lovvI speed, say two revolutions per ing a contouredsurface of revolution on a round minute.H A flange `32 on the rear of-the` shaft is Work-piece. Another object is to providea grind ,vsecured by bolts 34 toa rotary feeding wheel orV ing machine in whichthe advantages of oscillat- 2? carrier 3,61Whichis dished to forni-arecess 38 reing and centerless grinding by the infeed method ceivingtheend of va" shaft carrying a regulating are combined. Y 4WheelllZ-'Whoseperipheral surface is contoured to To these ends and alsoto improve generally t thework W which in this instance is a barrel uponmachines and methods of this character, shape'droller. Theshaft, ll isjournalled in a the invention consists in the various matters 30bearingMi` on a standard 48 Whose base is slidhereinafter described andclaimed. In its ablyfadjustable transversely of the shaft in a broaderaspects, the invention is not necessarily slideway 5l] carried on the.oscillating bed. limited to the specific ,constructions and steps Anarrow standard 52` is secured by bolts 54 to selected for illustrativepurposes in the accom-v ,u the bed@ at aj point near the axis I il ofoscillapanying drawings in Which- 'f5-J tQI1.` The upper portion of thestandard is re- Fig. 1 is alfront elevation of the machine with cessedopposite to the periphery ofthe carrier 36 some parts broken away andsome in section. towljeeive a removable guide or thrust plate 5t Fig. 2is an end elevation of Fig. l With the Whi'chlisfastened by "screws 58.Opposed to the grinding Wheel removed. y regulatingvvheelto form Vaconverging grinding Fig. 3 is a plan View of a portion of the mathroatisa grinding Wheel Whose periphery is chine, the feeding wheel being insection. contoured like` that of the regulating Wheel and Fig. 4 is aside View of a portion of the feeding the work. The grinding Wheelrotates downwheeL Wardly atthe work at high speed and the regulat- Fig.5 is an end view of Fig. 4. 4 3 ing-Wheel rotates upwardlyA at the WorkatmuchL Fig. 6 is a side View of a portion of a thrust plat-e.

Fig. 7 is a plan View` of a Work supporting blade.

Fig. 8 is a front vieW of Fig. 7.

Fig. 9 is a right hand end view of Fig.. 8.

Fig. l0 is a view similar to Fig. 8, the blade beespecially adapted togrind the peripheries of i' barrel-shaped rollers for bearings but itwill be understood that the machines can readily be adapted to generateconcave, convex, conical or other surfaces of revolution on a variety ofobjects.V Such rollersproduced by cold heading or by turning lathes, forinstance, are preferably end ground to accurate length tolerances withthe-end faces flat and normal to the axis. These pieces are then readyto have the surface of revlovver""speed.` Both wheels areI adjustableto- Wards the axis of oscillation to ,provide for wear, thegrindingWheel having a suitable slide (not shovvfforthis purpose.A Preferably,all of the nartsdescribed except the grinding Wheel oscil late as a'unitaround the vertical axis lt through a short a'rc,the` broken lineposition of Vthe, grindinghhvvheel,in"` Fig. 3 indicating the relativeoscillation `which occurs between the grinding wheel onthe" one' handand the remaining parts on the other hand. The axis' of oscillation isin the lplane of the grinding wheel and passes through the center oftransverse curvature of the grinding wheel periphery.

The carrier 36 (see Figs. 4, 5 and 1l) has its periphery provided with aseries of equally spaced teeth alternating with notches 12. The carrierpreferably moves down at the grinding throat and the leading face 14 ofeach tooth is substantially radial or parallel to a closely adjacentradius. The face 14 lies at right angles to the bottom wall '|6 of thenotch While the rear face 18 of each tooth is perpendicular to thebottom wall 16 and parallel to the face 14. Extending perpendicularlyinto each bottom wall 16 is a tapped opening 80 for a blade fasteningscrew as will appear. That side of the carrier facing towards the thrustplate 56 has a flat annular face outside of a circular rib 82 to receiveand support a toothed guide or thrust plate 86, see Fig. 6. The thrustplate 86 may be in the form of a single ring or may be in segments andit is removably attached to the side face of a carrier by screws 84.'The thrust plate 86 has a series of teeth 88 alternating with taperednotches 80.

The rear faces 92 of the teeth 88 substantially -v coincide crosswisewith the rear faces 'I8 of the carrier teeth and each tooth 88 coversone side of a tooth 16 and a portion of an adjacent notch l2. The bottomwall 94 of each notch 96 is straight and substantially aligns with thebot- Y' tom wall 16 of a carrier notch 12. The leading face 96 of eachtooth 88 slants at, say 25, to a radius.

A work supporting blade is removably carried in each notch and comprisesan attaching or supporting portion |88 of rectangular section secured bya screw |82 entering the tapped opening 88. The portion |60 of eachblade ts the tooth faces 14 and 18 and the bottom wall 16 of a notch l2.A narrow section |04 of each blade is of the same thickness as thetoothed thrust plate 86 and fits a tapered notch 9U of the thrust plate86, thev narrow section of the blade having an upper wall |66 providedwith the same inclination as the face 95 and engaging the latter. Theblade has an extended portion |08 projecting laterally beyond the plate86 over the regulating wheel periphery and into the space between thegrinding wheel and the regulating wheel where it is provided with anupwardly and inwardly facing or bevelled surface ||0 which is laterallycontoured to conform to the work. The outer surface of the blade iscurved as at ||2, the center of curvature preferably being at the axisof oscillation and this places the work supporting portion of the bladeclose up to the contoured periphery of the grinding wheel 66 and justoutside of the periphery of the regulating wheel 42. The work isconveniently supplied to the carrier from a magazine indicated at |4 andpreferably arranged above the grinding throat and terminating near thetop of the thrust plate 56.

As the feeding member or carrier 36 slowly turns clockwise, a work-pieceW drops onto each contoured and inclined blade surface ||0 between thexed thrust plate 56 and one of the teeth 88 of the rotary thrust plate86, the two thrust plates being parallel and spaced slightly fartherapart than the length Vof the work and actingr as guides for the endfaces of the work. The next piece is held back by the curved surface ||2of the next blade until the carrier turns enough to let such next piecedrop onto that next blade. The carrier moves each piece slowly downsidewise while supported by the blade and the regulating wheel, thepiece being rotated by contact with the regulating wheel which is movingin a direction opposite to that of the carrier. As the piece moves downto the grinding throat it is gradually ground to size, the carrier,thrust plates and the regulating wheel making several oscillations as aunit while grinding occurs. The carrier rotation may be intermittent ifdesired and the movement is desirably fast while the work is brought togrinding position and then slow so that suicient oscillation strokes canoccur at the grinding zone to generate an accurate contour. When thecompleted piece is carried below the grinding throat, it drops off theblade. The contour of the wheels is maintained by suitable dressingdevices (not shown).

I claim:

l. In a machine for generating a curved surface on a round work-piece, agrinding wheel and a regulating wheel spaced apart to form a grindingthroat, a thrust plate extending along one side of the grinding throat,a movable feeding member at the other side of the grinding throat andhaving a Work supporting blade extending towards the thrust plate andadapted to travel through the throat peripherally of one of the wheels,and means providing for a relative movement of oscillation around anaxis, between the grinding wheel on the one hand and the regulatingwheel, feed member and thrust plate on the other hand; substantially asdescribed.

2. In a machine for generating curved surfaces on round work, a grindingwheel and a regulating Wheel spaced apart to form a grinding throat, theperipheries of the Wheels being contoured to conform to opposite sidesof the work, a feeding Wheel alongside of the regulating wheel andhaving a plurality of worlf` supporting blades projecting over theperiphery of the regulating wheel, each blade having a contoured surfaceto conform to the work, a thrust plate extending along one side of thegrinding throat to guide the ends of the work, means for slowly rotatingthe feeding wheel around an axis to traverse the work supporting bladesthrough the grinding throat, and means operating during the travel ofthe blades to provide for oscillation around another axis of theregulating wheel, blades and thrust plate as a unit; substantially asdescribed.

3. In a machine of the character described, a grinding wheel mounted torotate on a fixed axis, a bed mounted to oscillate around an axis in theplane of the grinding Wheel, a regulating wheel mounted on theoscillating bed and having its periphery opposed to that of the grindingwheel to form a grinding throat, a thrust plate mounted on theoscillating bed and closing one side of the grinding throat, a feedingmember mounted on the oscillating bed and having a thrust plate closingthe other side of the grinding throat, work supporting blades projectinginto the throat from the feeding member, and means for rotating thefeeding member around an axis to traverse the blades slowly through thethroat while the bed and the parts supported thereby are oscillatedaround the bed axis; substantially as described.

4. In a machine of the character described, a grinding wheel and aregulating wheel spaced apart to form a grinding throat, a feeding wheelalongside of the regulating wheel and having its periphery notched, athrust plate secured to the feeding wheel and having its peripherynotched, and work supporting blades secured in the notches andprojecting laterally over the periphery of the regulating wheel;substantially as described.

5. In a machine of the character described, a grinding wheel and aregulating Wheel having their peripheries spaced apart to form agrinding throat, a feeding Wheel alongside of the regulating Wheel, athrust plate secured to the feeding wheel and having its peripherynotched, Work supporting blades secured to the feeding Wheel andprojecting through the notches of the thrust plate into the grindingthroat; substantially as 5 described.

RAYMOND H. CRAMER.

